Drop table feature
The syntax you use to create the table determines the default behavior when you drop the Iceberg table from Hive or Impala.
If you use CREATE TABLE, the external.table.purge flag is set to true. When the table is dropped, the contents of the table directory (actual data) are removed. If you use CREATE EXTERNAL TABLE from Hive, the external.table.purge flag is set to false. Dropping a table purges the schema only. The actual data is not removed. You can explicitly set the external.table.purge property to true to drop the data as well as the schema.
To prevent data loss during migration of a table to Iceberg, do not drop or move the table during migration. Exception: If you set the table property 'external.table.purge'='FALSE', no data loss occurs if you drop the table.
Hive or Impala syntax
DROP TABLE [IF EXISTS] table_name
Hive or Impala example
ALTER TABLE t SET TBLPROPERTIES('external.table.purge'='true'); DROP TABLE t;